Jiangsu Engineering Laboratory for Environment Functional Materials, Huaiyin Normal University, Huai'an, 223300, China; Institute of Environmental and Sustainable Development in Agriculture, Chinese Academy of Agricultural Science, Beijing, 100081, China.
School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
J Hazard Mater. 2020 Dec 5;400:123038. doi: 10.1016/j.jhazmat.2020.123038. Epub 2020 Jun 15.
Flue gas desulphurization gypsum (FGD) is a major solid waste in coal-fired energy plants, and the appropriate reuse of this resources is still a major challenge. In this study, the feasibility of FGD as a calcium source to produce hydroxyapatite (FGD-HAP) for the immobilization of lead (Pb) and cadmium (Cd) in spiked soil was investigated. The effects of FGD and FGD-HAP on soil properties and redistribution, bioaccessibility and plant uptake of Pb and Cd were examined. Results showed that application of FGD and FGD-HAP could significantly improve the enzymes activities of contaminated soils, but the effectiveness was more pronounced with FGD-HAP. Addition of only 1% FGD-HAP could effectively reduce bioavailable Pb and Cd concentration in soil as measured by CaCl extraction by 60.6% and 65.4%, respectively. On the other hand, plant available Pb and Cd could significantly decrease by 93.8% and 73.2% after amendment of 5% FGD-HAP. Significant changes in the micro-scale distribution of heavy metals before and after FGD-HAP treatment demonstrated that while heavy metals were predominantly associated with iron/manganese oxides in untreated soil, high correlation between heavy metals and phosphorus/sulfur was observed in FGD-HAP treated soil. In addition, results of the leaching tests showed that incorporation of FGD-HAP enhanced the retention capacity of heavy metals in soil, indicating that application of FGD-HAP could diminish the environmental risk of leachable heavy metals to groundwater. Overall, this study highlighted the potential value of FGD-HAP as a low-cost and high-efficient amendment for remediation of Pb and Cd contaminated soils.
烟气脱硫石膏（FGD）是燃煤能源厂的主要固体废物，而这种资源的适当再利用仍然是一个主要挑战。在这项研究中，研究了 FGD 作为钙源生产羟基磷灰石（FGD-HAP）以固定污染土壤中铅（Pb）和镉（Cd）的可行性。研究了 FGD 和 FGD-HAP 对土壤性质和再分布、Pb 和 Cd 的生物可利用性和植物吸收的影响。结果表明，FGD 和 FGD-HAP 的应用可以显著提高污染土壤的酶活性，但 FGD-HAP 的效果更为明显。仅添加 1%的 FGD-HAP 就可以有效地将土壤中可利用的 Pb 和 Cd 浓度分别降低 60.6%和 65.4%，通过 CaCl 提取测量。另一方面，添加 5%FGD-HAP 后，植物可利用的 Pb 和 Cd 可分别显著降低 93.8%和 73.2%。FGD-HAP 处理前后重金属的微观分布发生了显著变化，表明在未处理的土壤中，重金属主要与铁/锰氧化物结合，而在 FGD-HAP 处理的土壤中，重金属与磷/硫之间存在高度相关性。此外，淋滤试验的结果表明，FGD-HAP 的掺入增强了重金属在土壤中的保留能力，表明应用 FGD-HAP 可以降低可浸出重金属对地下水的环境风险。总的来说，这项研究强调了 FGD-HAP 作为一种低成本、高效的修复 Pb 和 Cd 污染土壤的改良剂的潜在价值。
